Not Applicable
Not Applicable
This invention relates to methods for detecting the position or state of an object, and more particularly, using optical means to confirm that a specific object is in a specific desired location, orientation, or state.
It is often required to confirm, from some distance, for example, that a mechanical or other device is in a specific position or configuration, or that an electrical device is powered on or off, that a residential sliding or hinged door is closed and also locked, or that a stove element is not left on for an extended time after use. Prior art has proposed a variety of solutions.
For example, U.S. Pat. Nos. 3,643,249 to Haywood, 4,453,390 to Moritz et al., 4,559,796 to De Forrest, Sr., 4,683,741 to Fields, 4,760,380 to Quenneville et al., 4,912,456 to Mickel, 5,062,670 to Grossman, and 5,111,007 to Miller et al. each disclose an apparatus or system to monitor and indicate whether a door lock set is in the locked position. However, these all require that a specially designed door lock set or mechanism be used, or that special modifications be made to the lock set mechanism or door. Also, as the monitoring method is electrical in nature and is mounted in the door, remote monitoring from the moving or swinging door is difficult as cabling to a moving device always presents several problems (such as how to route the cable, and fatigue of the flexing cable). And local monitoring (that is, a stand-alone unit with no external cabling) requires battery operation, which presents other problems (such as the requirement to change the battery periodically, and the difficulty or expense of remotely monitoring the door locked status, for example by using radio frequency transmission). U.S. Pat. Nos. 4,394,584 to Spahui et al. and 4,507,654 to Stolarczyk et al. can show that a door or window is closed but not whether it is locked. Also, they require the installation of cabling to the door or frame, or a battery-operated device to be located at the door or window, and again, this creates a maintenance and remote monitoring problem. U.S. Pat. Nos. 3,710,052 to Jette, 4,717,909 to Davis, 5,257,841 to Geringer et al., and 5,825,288 to Wojdan, are special assemblies that must be mounted in a door frame to monitor the position of the lock bolt, and as such require a difficult installation procedure of the assembly into the door frame, as well as of cabling to the assembly in the door frame. Also, the assemblies must be compatible with the type of lock and bolt installed, and also require careful mechanical alignment. Finally, these are electromechanical devices, and as such have electrical contacts that can wear out or corrode, have moving mechanical parts that can break or require realignment, and as these devices are accessible from the door frame""s mortise, they are vulnerable to damage and vandalism.
And in any case, the above solutions are all specific to doors and windows, and not to the myriad of other monitoring applications, such as stove control dials and sliding doors.
There are many systems described in the prior art for detecting changes in volumes of space. For example, U.S. Pat. Nos. 3,886,549 to Cheal et al., 4,027,303 to Neuwirth et al., and 4,319,332 to Mehnert are intended as security systems to detect new or missing items on a surface, or in a region space. However, these are not well suited to detecting the following; changes in position or orientation of a smaller specific object in that spacexe2x80x94especially in the presence of larger objects, or small changes in position of those larger objects in the monitored region, or very slow changes. Also, these are complex systems with microwave radio frequency operation, significant processing requirements to characterize, store, and compare the state of successive scans of the region, and/or other characteristics which result in high construction costs.
Other prior art discloses methods to count or detect objects passing through an area, for example to count items on a conveyor belt or stop a machine if an obstruction is detected in a particular zone. Examples include U.S. Pat. Nos. 3,889,118 to Walker, 4,590,410 to Jonsson, 4,659,922 to Duncan, 5,250,801 to Grozinger et al., 5,416,316 to Kappeler, 5,812,058 to Sugimoto et al., and 5,852,292 to Blxc3xcmcke et al. However, these have one or more of the following shortcomings; not directional to a specific location, cannot detect the movement or rotation of a specific part of a larger object, or are too limited in the distance to the sensed object.
U.S. Pat. No. 5,475,367 to Prevost discloses a system for detecting the continued presence of valuable items. However, this requires a detector unit to be mounted close to the monitored object, and in any case, is not well suited to detecting small changes in position or rotation of a part of a larger object.
U.S. Pat. No. 5,854,520 to Buck et al. discloses a timer to control the duration that power is applied to the burners of a stove. However, this system requires either substantial modification to an existing stove""s controls and electrical system, or that the stove be initially manufactured with the required relays and circuitry. Other inventions also require special wiring to a stove or oven, and mechanical switches to be retrofitted or incorporated into the stove controls and/or other assemblies. For example, U.S. Pat. No. 3,852,728 to Flagg, Jr. discloses an alarm that provides a continuous indication when a stove element is on, and an intermittent indication for a period afterwards, while the stove element cools. This has the problems that users would become so accustomed to the alarm that it would provide little alerting value, there is no provision for remote monitoring, and high-temperature wiring and switches must be installed in the stove. U.S. Pat. Nos. 4,334,145 to Norris, Sr., 4,446,455 to Nashawaty, and 4,577,181 to Lipscher et al. disclose an alarm which detects when a stove element is powered on but there is no utensil placed onto the corresponding stove element. This requires mechanical modifications to be made to the stove to accommodate a specially designed switch, a switch to be attached to each burner assembly, the switch and wiring to be suitable for high-temperature operation, and the switch and assembly to be kept clean so movement is not impeded. Additionally, it does not alarm if the stove element is left on with a utensil on the burner, and does not allow for remote monitoring of the switch status. U.S. Pat. No. 5,608,378 to McLean et al. discloses a system to alert a user if a stove element is turned on and then a dwelling exit door is openedxe2x80x94for example to leave the dwelling. This has the problems that electrical wiring is required to the stove control or indicator light and also to the exit door, that the alarm will sound if the door is opened for another purpose (for example when another member of the family arrives home for dinner), and that the system is of no value if the home-owners leave through an alternate door, or leave the stove on all night while they sleep.
And in any case, the above solutions are all specific to stoves, and not to the myriad of other monitoring applications.
U.S. Pat. No. 4,063,044 to Stephan discloses a system utilizing photocells to monitor the line-busy lights on a telephone. However, the photocells must be placed directly over the lights, the invention is described for use with multi-line telephones only, and alarming is described only when all lights are illuminated (rather than when any one is illuminated, which is more meaningful for security purposes).
Clearly, there is a need for a method of remotely sensing, for example, whether a door is locked, or whether a stove is turned off, without the limitations, installation difficulties and other undesirable features of the prior art.
It is an object of the present invention to provide a method to detect that a specific object is in a specific location, orientation, or state. For example, through monitoring existing surfaces of existing devices, to detect whether a door or window is not only closed but also locked, or whether a fixed appliance with a movable or rotatable control dial, such as a stove, is turned off. Or that a piece of equipment is in a certain location, or that a pane of glass is intact, or that a safe""s door is fully closed and the handle in the locked position, or that a machine is or control lever is in a certain position. And such monitoring be accomplished by detecting small changes in the position or orientation of objects such as a door locking lever or stove control dial. Or, through monitoring the existing indicator lights of existing devices, to detect whether the device is powered on or not.
It is a further object of the present invention that no, or little, modification or installation effort be required for the objects or devices to be monitored, so that a wide variety of existing or newly designed items, devices and appliances, such as doors, windows, drawers and stoves can be monitoredxe2x80x94and without requiring special assemblies or mechanisms to be designed for, or installed in, or attached to the items, devices or appliances.
It is a further object of the present invention that the monitoring of the items, devices and appliances can be done from a distance, without requiring cabling to be run right to themxe2x80x94since installing cabling is often problematic; as it requires tools and skills, and hiding cabling is difficult, time-consuming and damages walls. And opening items, devices and appliances in order to retrofit switches, and running cabling to them can be dangerous due to the hazardous voltages present in them, and also can void manufacturer warranties. Finally, the present invention also allows some flexibility in the remote mounting location of the monitoring device, both so that it can be unobtrusive, and also to facilitate the installation of any cabling to the monitoring device required.
It is a final object of the present invention that the remote monitoring of the items, devices and appliances be done without the use of radio frequency transmission from the items, devices and appliances, as some people are concerned that there may be health implications to spending substantial amounts of time near radio frequency transmitters. Also, radio frequency transmissions both are subject to interference from other devices, and can cause interference to other devices. Finally, radio frequency transmitters require power supplies, and if these must utilize batteries in order to avoid the use of cabling, then there is the on-going cost of periodically replacing the batteries, as well as the environmental cost of disposing of the used batteries.
In the descriptions herein, the term xe2x80x9chandlexe2x80x9d shall equally refer to any mechanical lever or slider, electrical switch handle, control knob or dial, or any other movable part, which may or may not be part of another item, device or appliance, whose position is to be monitored.
Also, the terms xe2x80x9cmovementxe2x80x9d or xe2x80x9cpositionxe2x80x9d shall equally refer to the rotation, orientation, angle, translation or other possible degrees of freedom of such handles.
And, the term xe2x80x9cdesired positionxe2x80x9d refers to a position of the object which is to be confirmed, for example, that a door is fully closed and also locked, or a stove control dial is in the off position. Alternatively, for objects that have a limited number of possible positions, it could be confirmed that an object is in a desired position by determining the conversexe2x80x94that is, that the object is not in any of the undesired positions. Also, an object could also have more than one desired position.
Finally, the term xe2x80x9cindicator lightxe2x80x9d refers to any source of electromagnetic energy, whose intensity or other characteristic is to be monitored in order to detect the state of an item, device or appliance. Typical examples would be a power on or other mode of operation indicator light on an appliance or piece of electronic equipment.
In a first embodiment of the present invention, a small retroreflective surface is affixed to the handle of the item, device or appliance to be monitored. For example, a 5 mm diameter, self-adhesive dot of 3M Company""s Scotchlite is applied to the lock handle on a residential exterior sliding door. A monitoring device is then aimed so that it projects a narrow beam of light at the position where the retroreflective surface on the handle would be when the door is fully closed and locked (that is, in the desired position). Then, whenever the handle is in the desired position, the monitoring device will receive the retroreflected light. And when the handle is not in the desired position (for example, the door is closed but not locked, or the door is open but the handle is in the xe2x80x9clockedxe2x80x9d position), the monitoring device will not receive any retroreflected light. Thus, when the monitoring device receives retroreflected light there is assurance that the door is both fully closed and locked. To report the detected status, an electronic circuit in the monitoring device implements some combination of: a visual and/or audible indication or alert, relay contact output, delay timer, radio frequency or other transmitter, data interface or other means to convey the door status to nearby people, or to a burglar alarm system, network, or other device.
In a second embodiment of the present invention, the retroreflective surface is affixed to a surface to which the light beam from the monitoring device (which has been aimed at the retroreflective surface) is alternately obstructed or unobstructed, depending on the position of the handle being monitored. For example, when the handle is in the desired position the light beam can and does impinge on the retroreflective surface, and this light is retroreflected back to the monitoring device. And when the handle is not in the desired position, the handle obstructs the light path to the retroreflective surface, so no light is retroreflected back to the monitoring device. An example of when this embodiment would be useful is when there is a problem in affixing the retroreflective surface to the handle itself, perhaps because the handle has an irregular shape or the retroreflective surface would get quickly covered with dirt or worn off if it was attached to the handle. This second embodiment is also useful as the aiming of the light source need not be as accurate as for the first embodiment above, and this is described further below.
In another embodiment of the present invention, the retroreflective surface is attached to the interior surface of the glass of a door or window. This can serve as a glass breakage detector for a burglar alarm systemxe2x80x94since the breakage of the glass would cause the location of the retroreflective surface to move substantially, and this would be detected by the monitoring device. Or the retroreflective surface could be attached to the interior surface of a door or the frame of a window, so opening the door or window would cause the location of the retroreflective surface to move substantially, and this would also be detected by the monitoring device. While these two types of security monitoring are traditionally done by ultrasonic glass breakage detectors and magnetic reed switch contacts, there are situations where such traditional means are not suitable. For example, when installing the requisite cabling or sensors to the window or door may not be possible due to; a requirement for a temporary installation or not damaging walls (for example, in a rented facility or a historic building), building construction in which it is difficult to run cabling, an architectural or aesthetic requirement to conceal security systems, a hazardous environment where the use of electrical cabling is restricted, the need for a simpler installation procedure (for example, so a consumer can do it themselves), or some other special situation.
In another embodiment of the present invention, the optical assembly of a monitoring device is focussed so that it gathers light directly from the item, device or appliance to be monitored. For example, from the power on indicator light of an appliance. The power on status of the appliance can then be detected without requiring a special switch to be installed in, or cabling to be installed directly to, the appliance. Additionally, this method avoids potential safety issues concerned with potential contact with dangerous voltages in an appliance. In order to reduce the effect of ambient light, a light-absorbing surface may need to be installed around the indicator light, or an optical filter assembly may need to be used in the received light path.